Assembly with two indexed parts

ABSTRACT

In one exemplary implementation, an assembly may include two indexed parts. A first part may have a void formed therein and an axis, with the void defining at least one rotational stop and at least one radial stop. A second part may have a projection that is received at least partially in the void when the first and second parts are assembled together. The projection may have at least one rotational abutment surface adapted to engage said at least one rotational stop to limit relative rotation between the first and second parts, and the projection having at least one radial abutment surface adapted to engage said at least one radial stop to limit relative radial movement between the first and second parts in a direction away from the axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from French Patent Application No. 0858254 filed Dec. 4, 2008, the contents of which is hereby incorporated by reference.

TECHNICAL FIELD

The disclosure relates to a mechanical assembly with two indexed parts, such as a pumping mechanism, whose body houses one or more pumping elements.

BACKGROUND

There exist several ways to index parts relative to one another. With regard to liquid pumping devices, limitation of the movement between different parts is effected by indexing features, namely nipples or bosses, used to limit rotary motion of the different parts of the pumping element. However, this type of indexing limits travel in one direction only. This can result in a relatively weak retention of the different parts, undesirably large relative movement between the parts, or even separation of the components during the assembly of the pump.

SUMMARY

In at least one exemplary implementation, an assembly may include two indexed parts. A first part may have a void formed therein and an axis, with the void defining at least one rotational stop and at least one radial stop. A second part may have a projection that is received at least partially in the void when the first and second parts are assembled together. The projection may have at least one rotational abutment surface adapted to engage said at least one rotational stop to limit relative rotation between the first and second parts, and the projection having at least one radial abutment surface adapted to engage said at least one radial stop to limit relative radial movement between the first and second parts in a direction away from the axis.

In one exemplary implementation, a pumping assembly may include a first body, a second body and at least one pumping element. The first body may have a void formed therein and an axis, with the void defining at least one rotational stop and at least one radial stop. The second body may have a projection that is received at least partially in the void when the first and second parts are assembled together. The projection may have at least one rotational abutment surface adapted to engage said at least one rotational stop to limit relative rotation between the first and second parts, and the projection may have at least one radial abutment surface adapted to engage said at least one radial stop to limit relative radial movement between the first and second parts in a direction away from the axis. The pumping element may be disposed at least partially between the first and second bodies.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of exemplary embodiments and best mode will be set forth with reference to the accompanying drawings, in which:

FIG. 1 is a pumping assembly with conventional indexing features;

FIG. 2A is a fragmentary perspective view of the pumping assembly of FIG. 1;

FIG. 2B is a perspective view of an upper component of the pumping assembly of FIG. 1;

FIG. 3 is a plan view of a lower component of the pumping assembly of FIG. 1;

FIG. 4 is an exploded perspective view of an exemplary pumping assembly;

FIG. 5 is a fragmentary perspective view of the pumping assembly of FIG. 4;

FIG. 6 is a plan view of a pump body of the pumping assembly of FIG. 4 that includes a projection; and

FIG. 7 is a plan view of an exemplary pumping element that may be used in the pumping assembly of FIG. 4.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

Referring in more detail to the drawings, FIGS. 1-3 illustrate a conventional pumping element 1 that includes two components 10, 20, which can be upper and lower end caps or a housing of the pumping element. As shown, the two components 10, 20 of the pumping element 1 have a generally cylindrical shape and an axis of rotation Z. Indexing along axis Z of the components 10, 20 of the pumping element 1 is effected by indexing features 35 composed of two parts, namely a groove 30 in component 20, and a tab 40 in component 10, with the shapes of the groove and of the tab 40 being complementary.

The groove 30 includes two side walls 32, a rear wall 34 and a bottom 36. It is of generally parallelepiped shape, with the side walls 32 parallel, and the rear wall 34 curving inward and defined by a cylinder of revolution around the Z axis. The bottom 36 is in a plane that is perpendicular to the axis Z. The tab 40 also has two side walls 42, a rear wall 44 and a lower wall 46. The shape of the side walls 42 and of the rear wall 44 of the tab 40 is similar to the shape of the side walls 32 and of the rear wall 34 of the groove 30.

During assembly, in which the components 10, 20 are brought together by a linear movement along the axis Z, the lower wall 46 butts up against the bottom 36, thus limiting the movement of the parts of the pumping element along the direction of the axis Z. The rear wall 34 of the groove 30 will also act as a stop for the rear wall 44 of the tab 40, and thus limits the motion in the direction of arrow E. The side walls 42 of the tab 40 will butt up against the side walls 32 of the groove 30, thus limiting the rotary movement of the components around the axis Z. However, as shown in FIG. 3, motion in the direction of arrow D remains possible, and can lead to the components 10, 20 becoming separated and/or dropped during assembly. That is, the tab 40 can slide radially out of the groove 30 in the direction of the arrow D.

One exemplary embodiment of a fuel pumping assembly 50 including two components that have indexing features that prevent radial and rotational movement of the components is shown in FIGS. 4-7. The two components of the pumping assembly 50 may include upper and lower pump bodies 52, 54 between which one or more pumping elements 56 (FIG. 7) may be received. The pumping element 56 may be an impeller having a plurality of vanes 55 or blades (as shown, or of a different construction), a gerotor set, or any other suitable mechanism or device. The upper and lower pump bodies 52, 54 may include generally opposed, planar surfaces 56, 58 that are oriented perpendicular to the axis Z. The surface 56, 58 of one or both of the upper and lower pump bodies 52, 54 may be recessed relative to an outer peripheral edge 60, 62 of the bodies to facilitate receipt and enclosure of the pumping element(s) 56 between the bodies. A pumping channel 57 may be defined at least in part between the pumping element 56 and at least one of the upper body 52 or the lower body 54. The pumping channel 57 may have an inlet 59 into which fuel enters the pumping channel at a first pressure and an outlet from which fuel exits the pumping channel at a second pressure that is higher than the first pressure, as is known in the art.

The indexing features may include a void 64 and a projection 66 adapted to be received in the void. The void 64 may be in the form of a slot, groove, cavity, or the like, and may be a generally parallelepiped shaped void with one or more open sides, a partial sphere, cylinder, or any other suitable shape. As shown, the void 64 is formed in the lower body 54 and the projection 66 is carried by or formed on the upper body 52. Of course, the void 64 could be formed in the upper body 52 and the projection 66 could be carried by the lower body 54, or the upper and lower body could each have more than one void and/or projection. That is, the each of the lower body 54 and upper body 52 may have one or more voids 64, one or more projections 66, or one or more voids and projections.

As shown in FIG. 5, the void 64 may define side walls 70, an inside wall 72 and a bottom 74. The sidewalls 70 may define part of a radially oriented opening 76 that is spaced from the inside wall 72 generally at the periphery 62 of the lower body 54. That is, the opening 76 may be the radially outermost portion of the void 64, relative to the axis Z. The opening 76 may have a circumferential length that is less than a portion of the void 64 that is radially inwardly spaced from the opening 76. As shown, for example, the void 64 becomes longer (circumferentially) in the direction from the opening toward the inside wall 72. Here, the void 64 takes the form of a dovetail, but could equally well have other shapes, such as being formed with arcuate or rounded side walls, zig-zag side walls, concave or convex side walls, or other shapes.

As shown in FIGS. 5 and 6, the projection 66 may be complementarily shaped to the void 64. In this way, the projection 66 may have an end 80, side walls 82 and an inner wall 84 that are adapted to be positioned adjacent to the bottom 74, side walls 70 and the inside wall 72, respectively, of the void 64. The projection 66 may also have a radially outer edge 86 (or edge portion) with a circumferential length that is less than at least a portion of the projection 66 that is radially inwardly spaced from the outer edge 86. As shown, the projection 66 becomes longer (circumferentially) as the projection extends radially from the outer edge 66 to the inner wall 84. The side walls 82, 70 of the projection 66 and the void 64 may be oriented at similar or different angles. In the example shown, the side walls 70 and 82 are oriented at similar angles relative to the axis Z. Also in the embodiment shown in FIGS. 4-6, the sidewalls 70 of the void 64 and the sidewalls 82 of the projection 66 converge in the radial direction away from the Z axis.

The void may define at least one rotational stop and at least one radial stop. In the implementation shown, the radial stop limits radial movement of the upper body 52 relative to the lower body 52 in a direction away from the axis Z when the projection 66 is at least partially received in the void 64. In the implementation shown, the sidewalls 70 of the void 64 define rotational stops that are engaged by the projection to limit relative rotational movement between the upper and lower bodies 52, 54 in each of a pair of opposed directions relative to the axis Z (e.g. clockwise and counter-clockwise). The sidewalls 70 also define the radial stop that limits radial movement of the upper body 52 relative to the lower body 52 in a direction away from the axis Z. Another radial stop is defined by the inside wall 72 of the void, which limits radial movement of the upper body 52 relative to the lower body 52 in a direction toward the axis Z. In this way, the void provides a pair of radial stops and a pair of rotational stops. In this regard, while the void 64 shown includes an opening 76, the void need not have a radially oriented opening, and may instead have only an axially facing opening (e.g. opposite the bottom 74). The void 64 and projection 66 may be located circumferentially closer to the inlet than the outlet of the pumping channel 57. The void 64 and projection 66 may also be located circumferential between (although they may be radially outboard of) the inlet and the outlet of the pumping channel 57. To limit rotational and radial movement as noted, the void 64 and projection 66 may, but need not, be complementary in shape.

During assembly, the upper and lower bodies 52, 54 are brought together in a linear movement along the axis Z, so that the projection 66 is received in the void 64. If desired, the end 80 of the projection 66 may engage the bottom 74 of the void 64, thus limiting the movement of the bodies along the direction of the axis Z. Otherwise, the axial length of the projection 66 may be less than the axial depth of the void 64 so that, with normal manufacturing tolerances, the faces 56, 58 of the upper and lower bodies 52, 54 engage, and the projection 66 does not engage the bottom 74 of the void 64.

While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention. 

1. A pumping assembly, comprising: a first body having a void formed therein and an axis, with the void defining at least one rotational stop and at least one radial stop; a second body having a projection that is received at least partially in the void when the first and second parts are assembled together, the projection having at least one rotational abutment surface adapted to engage said at least one rotational stop to limit relative rotation between the first and second parts, and the projection having at least one radial abutment surface adapted to engage said at least one radial stop to limit relative radial movement between the first and second parts in a direction away from the axis; and at least one pumping element disposed at least partially between the first and second bodies.
 2. The assembly of claim 1 wherein said at least one radial stop includes a pair of side walls of the void that have at least a portion that converge as they extend away from said axis.
 3. The assembly of claim 1 wherein said void defines a pair of opposed radial stops that are engaged by the projection to limit relative radial movement between the components in directions toward and away from the axis.
 4. The assembly of claim 3 wherein the void includes a pair of sidewalls that define said at least one radial stop and also define said at least one rotational stop.
 5. The assembly of claim 3 wherein the void includes an inside wall that defines a radial stop that limits relative radial movement between the components in directions toward the axis.
 6. The assembly of claim 1 wherein said void defines a pair of rotational stops that are engaged by the projection to limit relative rotational movement between the components in both clockwise and counter-clockwise directions relative to the axis.
 7. The assembly of claim 1 which also comprises a pumping channel defined at least in part between said at least one pumping element and at least one of the first body or the second body, the pumping channel having an inlet into which fuel enters the pumping channel at a first pressure and an outlet from which fuel exits the pumping channel at a second pressure that is higher than the first pressure, and wherein the void and projection are located circumferentially closer to the inlet than the outlet of the pumping channel.
 8. An assembly with two indexed parts, comprising: a first part having a void formed therein and an axis, with the void defining at least one rotational stop and at least one radial stop; and a second part having a projection that is received at least partially in the void when the first and second parts are assembled together, the projection having at least one rotational abutment surface adapted to engage said at least one rotational stop to limit relative rotation between the first and second parts, and the projection having at least one radial abutment surface adapted to engage said at least one radial stop to limit relative radial movement between the first and second parts in a direction away from the axis.
 9. The assembly of claim 8 wherein said at least one radial stop includes a pair of side walls of the void that have at least a portion that converge as they extend away from said axis.
 10. The assembly of claim 8 wherein said void defines a pair of opposed radial stops that are engaged by the projection to limit relative radial movement between the components in directions toward and away from the axis.
 11. The assembly of claim 10 wherein the void includes a pair of sidewalls that define said at least one radial stop and also define said at least one rotational stop.
 12. The assembly of claim 10 wherein the void includes an inside wall that defines a radial stop that limits relative radial movement between the components in directions toward the axis.
 13. The assembly of claim 8 wherein said void defines a pair of rotational stops that are engaged by the projection to limit relative rotational movement between the components in both clockwise and counter-clockwise directions relative to the axis.
 14. The assembly of claim 9 wherein the side walls are of concave form.
 15. The assembly of claim 8 wherein the side walls are of convex form.
 16. The assembly of claim 8 wherein the side walls are in the form of a dovetail. 